JSON Module

Matthew Williams

Edited by

Matthew Williams

Table of Contents

1. Admin Guide
1. Overview
2. Dependencies
2.1. Kamailio Modules
2.2. External Libraries or Applications
3. Functions
3.1. json_get_field(json_string, field_name, destination)
3.2. json_get_string(json_string, field_name, destination)
4. Transformations

List of Examples

1.1. json_get_field usage
1.2. json_get_string usage
1.3. json.parse usage

Chapter 1. Admin Guide

1. Overview

This is a simple module allowing to retrieve values from a JSON string.

For more complex operations with JSON documents, see the JANSSON module.

2. Dependencies

2.1. Kamailio Modules

The following modules must be loaded before this module:

  • None

2.2. External Libraries or Applications

The following libraries or applications must be installed before running Kamailio with this module loaded:

  • libjson (https://github.com/json-c/json-c/wiki)

3. Functions

3.1.  json_get_field(json_string, field_name, destination)

Copy field 'field_name' from json object 'json_string' and store it in pvar 'destination'.

Note that the result is the string representation of that JSON filed. For example, if you want to retrieve a field that has a string value, then the result is the value enclosed in quotes. If the field value is a structure, then the result is the string-formatted representation of that structure.

Example 1.1. json_get_field usage

json_get_field("{'foo':'bar'}", "foo", "$var(foo)");
xlog("foo is $var(foo)");

3.2.  json_get_string(json_string, field_name, destination)

Copy field 'field_name' from json object 'json_string' and store it in pvar 'destination'.

Example 1.2. json_get_string usage

json_get_string("{'foo':'bar'}", "foo", "$var(foo)");
xlog("foo is $var(foo)");

4. Transformations

You can use the transformation to extract values from the json structured pseudo-variables

  • json

    Example 1.3.  json.parse usage

    	# extract value of "Custom-Data" from $rb pseudo-variable and set it to $var(Custom-Data)
    	$var(Custom-Data) = $(rb{json.parse,Custom-Data});
    	if($var(Custom-Data) != $null) {	xlog("L_INFO", "$ci|log|custom data: $var(Custom-Data) from Request: $rb");